The Adult AIDS Clinical Trials Unit (ACTU) at UTMBG is applying for continuation funding for the years 2000 through 2004. This unit was established in 1992. During the next granting period the investigators intend to focus on three specific aims: Aim 1 is to study the immune system in patients with HIV infection by conducting studies using immunomodulators and other interventions that enhance immune responses. Laboratory studies will be conducted to produce new information on the immunologic consequences of active antiretroviral therapy in patients during successful suppression of HIV and in patients failing therapy. Aim 2 is to contribute to the development of optimal antiretroviral therapy that results in long-term suppression of HIV. An attempt will be made to simplify such regimens in order to facilitate adherence. Aim 3 is to investigate the influence of active antiretroviral therapy on the prevention of opportunistic infections (OIs) and to increase understanding of the risk factors for OIs. Studies designed to investigate the neurological complications and metabolic complication of HIV and of the therapies used to treat HIV are in this aim. Also included are long-term follow-up studies designed to understand how the natural history of HIV is influenced by therapeutic interventions. Aim 4 is to continue to emphasize studies in a special patient population, namely individuals incarcerated in the Texas Department of Corrections system. The investigators and staff at UTMBG propose to be active in the committee structure of the ACTG and to participate in the scientific agenda by being on protocol teams and assisting with study design. The location of an Immunology Support Laboratory at this site has contributed to participation in immunologic investigations. This is to continue to be a focus of this ACTU. The UTMBG ACTU site will continue to utilize the expertise of staff involved in clinical investigations.They are to gather all information on subjects in the studies in order to acquire the maximum scientific contribution of patient participation. Information developed during the next funding period is expected to contribute to the understanding of the pathogenesis of HIV infection and to continue improvements in clinical outcomes.